S49 Chesterfield Postcode district S49: 1 named streets and 8 live postcodes, in Chesterfield. Streets West Bars, Chesterfield Postcodes S49 1PF S49 1WW S49 1WX S49 1XX S49 1YX S49 1YY S49 1YZ S49 1ZS Source: ONS Postcode Directory (live postcodes only) and OS Open Linked Identifiers for the streets.